Axial flow reaction tower

ABSTRACT

An axial flow delayed combustion furnace or reaction tower for synthesis gas production for pressures greater than 10 atm., and temperatures greater than 700* C., is provided with an inner thermal lining, an arch for supporting the catalyst, the arch being of ring shape and such that a stack is disposed at the center thereof through which the gas-conducting pipe extends. The lower end of the gas pipe is mounted in a reinforced collar on the floor of the reaction tower, and is connected to the tower floor through a sleeve-shaped expansion part.

United States Patent [72] inventors Appl. No.

Filed Patented Assignee Priority Paul Mevenkamp Lichtendorf;

11ans-Dieter Marsch, Dortmund; Herbert Biskup, Dortmund-Aplerbeck, allof, Germany Apr. 2, 1970 Sept. 21, 1971 Friedrich Uhde GmbH Dortmund,Germany Oct. 25, 1966 Germany V 132151Va/12g Continuation-impart ofapplication Ser. No.

677, 67, 061. 24, 19 7, now abandoned.

AXIAL FLOW REACTION TOWER 2 Claims, 2 Drawing Figs.

US. Cl 23/288, 23/277, 23/283, 23/288 L, 23/289, 122/510 Int. Cl B01j9/04 Field of Search 23/288,

288.91, 288.92, 289, 277 US, 283 US, 284 US; 48/102 US, 107 US, 196 US,197 US; 196/133, 110; 122/510 US, 511 US 7% R1 ib 'n [56] ReferencesCited UNITED STATES PATENTS 1,833,188 11/1931 Larson 23/289X 1,839,738l/l932 Casale.... 23/289 2,280,089 4/1942 1-1oudry.. 23/288 L 2,472,2546/1949 Johnson 23/288 L X 2,614,033 10/1952 Cornell et al.. 23/2882,634,194 4/1953 Nebeck 23/288 FOREIGN PATENTS 330,872 6/1930 GreatBritain 23/288.92

Primary Examiner-Joseph Scovronek Attorney-Malcolm W, Fraser ABSTRACT:An axial flow delayed combustion furnace or reaction tower for synthesisgas production for pressures greater than 10 atm., and temperaturesgreater than 700C, is provided with an inner thermal lining, an arch forsupporting the catalyst, the arch being of ring shape and such that astack is disposed at the center thereof through which the gas-conductingpipe extends. The lower end of the gas pipe is mounted in a reinforcedcollar on the floor of the reaction tower, and is connected to the towerfloor through a sleeveshaped expansion part,

AXIAL FLOW REACTION TOWER CROSS-REFERENCE TO RELATED APPLICATION Thisapplication constitutes a continuation-in-part of application, Ser. No.677,667, filed Oct. 24, 1967, and entitled Axial Flow Reaction Tower(now abandoned).

BACKGROUND OF THE INVENTION The present invention concerns an axial flowreaction tower or delayed combustion furnace for the chemical conversionof highly heated and/or compresses reaction components in synthesis gasinstallations. Since the reaction tower is flowed through in an axialdirection, with known constructions one of the feeding or dischargepipes leads over the entire outer length to the head of the reactiontower. The removal of a transfer pipe of this kind involves considerabletechnical expense. The high-temperature load makes it necessary to makethe pipe out of high-alloy steel or to provide sufficient innerinsulation, and increased system pressure requires a correspondinglystrong construction of the pipe wall. Moreover, the control of adifferent heat expansion occurring between the outer pipe and reactiontower often causes great difficulties.

It is recognized that has may be conducted above the reactor floor bymeans of a central pipe, which is open at the top. Where the reactor isan almost pressureless vessel and no high temperature differences arepresent, the solution does not offer any difficulties. When the reactor,however, must be constructed for higher pressures, as for example atm.,the operating temperature of the reaction lies above 700C. and thetemperature differences between gas inlet and gas outlet pipes andbetween the latter and the sleeve temperature of the vessel areconsiderable, great difficulties occur in the construction of thepassages of bricklining or masonry, in order to attain perviousness andin the control of the heat expansion present with the necessary greatwall strengths. These difficulties were greater than the disadvantagesand difficulties of the previous construction of the conduit disposed onthe outside to the head of the delayed combustion furnace. For thisreason, this last-mentioned construction was maintained in spite ofeverything.

SUMMARY OF THE INVENTION It is an object of the invention to provide aninternally insulated reactor in which the catalyst rests upon aperforated supporting arch of high strength, said supporting arch beingshaped to prevent any adverse effect upon its function by the passage ofthe central gas-conducting pipe.

It is a further object of the invention to provide an internallyinsulated reactor in which an internally insulated gas feed nozzle andan internal gas-conducting pipe are connected to the bottom of thereactor, the internal gas-conducting pipe being mobile in a radialdirection and attached to the reactor bottom to form a gastight sealwhile extending to the head of the reactor and being open at the top.

Accordingly an axial flow delayed combustion furnace for synthesis gasproduction is provided for pressures greater than 10 atm., temperaturesgreater than 700C. with inner brick lining, catalyst supporting arch andlower gas feed through the floor of the delayed combustion furnace. Suchfurnace is characterized by forming the catalyst-supporting arch of ringor annular shape, and in such manner, that a stack or chute results inthe center. This stack or chute extends upwardly into the head of thedelayed combustion furnace by means of ceramic material within which isa gastight conduit pipe, which is attached to the gas feed conduit. Inorder to hold the gas conduit pipe in a central position within thefurnace, additionally on the upper end is a known guide piece whichpermits axial shifting.

A further feature of the invention consists in producing at the passagepoint of the gas-conducting pipe through the sleeve of the delayedcombustion furnace, a gastight elastic connection permitting of low heatdischarge between hot inner gas-conduction pipe and the only moderatelyhot sleeve of the delayed combustion furnace, so that the gas conductionpipe rests by means of a collar on a support bracket and is connectedgastight through a flexible expansion pipe with the sleeve of thefurnace.

The arrangement of the arch according to the invention insures a uniformflow across the catalyst bed because the gas path through the catalystbed, and the perforated arch and consequently the gas pressure drop fromthe catalyst bed inlet to the catalyst bed outlet on the perforated archis of the same level. If no provision were made for acatalyst-supporting arch, the lower part of the axial flow reactiontower would have to be filled with catalyst or with a filling materialthat leaves much free volume. Owing to gas paths of different lengthfrom the catalyst bed inlet through the catalyst and filling material tothe gas outlet nozzle, the flow distribution and, consequently thecatalyst load would be nonuniform. As compared to a dome-type supportingarch, an annular catalystsupporting arch has the advantage that, for anygiven diameter of the axial flow reaction tower, it provides betterstability to carry the considerable weight of the catalyst.

Through this arrangement according to the invention, the pipe leading tothe head of the reaction tower is exposed only to relatively slightstresses. The pressure load corresponds to the pressure loss found withthe flow inside the pipe and the reaction tower, while the temperaturedrop results from the temperature difference between the highly heatedreaction mixture in the inside of the pipe and the likewise hot contentof the reaction tower.

An inner pipe of this kind consequently, in comparison with a transferpipe led outside of the furnace, needs to exhibit only a low wallstrength and needs no, or only slight, insulation. Occuring heatexpansions are allowed for in simple ways through the unilateralreinforcement of the inner pipe at the floor of the reaction tower.Advantageously, moreover the pipe is set over a reinforced collar on asupport arranged on the floor of the reaction tower and is tightlyjoined independently with the tower floor by such a support constructionthrough a sleeveshaped expansion part. Through this kind of connectionof the pipe with the tower, heat expansions can also be compensated in aradial direction. At the head of the tower the pipe is guided axially ina suitable manner.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a vertical sectional view of anaxial flow reaction tower embodying the invention; and

FIG. 2 is an enlarged fragmentary sectional view of the lower endportion of the reaction tower.

DESCRIPTION OF PREFERRED EMBODIMENT The reaction tower 1 serves for thefurther conversion of the gas mixture coming out of a tube-crackingfurnace (not shown) which is heated to about 800C. This gas is leadthrough through the pipe 2 to the head 3 of the reaction tower and therereaches, with the addition of heated oxygen or air, a temperature ofabout 1200 C. With the passage of the gas mixture through the catalyst4, an endothermic reactiontakes place which causes a temperature dropnear the outlet connection 5 to about 970 C. The reaction tower is linedinside, for the protection of a steel shell 6, as well as for theprevention of greater heat loss, with a thick coat of insulationmaterial 7. The pipe 2 is only provided with an outer insulation stack8, which is to prevent the heat from being drawn from the reactionchamber 9 and which in addition protects the pipe 2 against directcontact with hot burning gas.

In the lower portion of the reaction tower or furnace is an annular arch4a on which the catalyst 4 is supported. The arch is of heat resistantmasonry and extends around the inside of the furnace as indicated onFIG, 1. The central portion 4b of the arch has an axial passage throughwhich the gas pipe 2 extends and has a shelf or ledge 40 on which thepipe-insulating stack 8 is supported. The arch 4a provides a free spaceover the entire cross-sectional area of the reaction tower.

In the bottom or floor part 10 of the reaction tower l the pipe 2extends through and is tightly connected to plate 11, which rests on asupporting bracket 12. A radially flexible expansion part 13 connectsthe plate 11 rigidly to the floor part 10. The bracket 12 is provided inthe upper part with recesses 12a in order to reduce the contact face andthereby to decrease the heat outflow from the gas-conducting pipe 2 intothe vessel sleeve. At the upper end 14 the pipe 2 has a guide piece 15which extends into the head 3 of the reaction tower, so that it canexpand unhindered in an axial direction.

From the above, it will be apparent that within the reaction tower l isa pipe 2 through which the highly heated or compressed reaction productspass. Through apertures at the top of the pipe the reaction productsenter the inside of the tower and after passage through the catalyst 4,and through the perforated arch 4a pass from the tower through theoutlet 5.

What We claim is:

1. An axial flow reaction for synthesis gas production for pressuresgreater than 10 atm. and temperatures higher than 700 C. comprising incombination an upright tower body having internal thermal insulation, acentral lower gas feed nozzle with internal thermal insulation, alateral gas discharge nozzle in the lower part of said body alsoprovided with internal thermal insulation, a central gas-conducting pipecommencing in said gas feed nozzle and extending vertically upward intothe upper part of the tower body and having an open end in the upperpart of said body, a radially flexible expansion part providing agastight connection between said gas feed nozzle and said gas-conductingpipe, said expansion part being surrounded by insulation, the spacebetween lower tower wall insulation and lower part of saidgas-conducting pipe being filled with a catalyst support structure inthe form of a ring-shaped arch which reaches to the tower bodyinsulation and surrounds said gas-conducting pipe, said arch beingperforated and the hollow space having a direct connection to the gasdischarge nozzle, said gas-conducting pipe having an outer insulationabove said ring-shape arch, the major portion of the space above saidring-shape arch being filled with catalyst, and said gas-conducting pipeterminating in the free space.

2. An axial flow reaction tower as claimed in claim 1, characterized inthat said expansion part consists of a plate attached to saidgas-conducting pipe by means of a gastight weld, said plate terminatingin a thin flexible part which is attached to the bottom of said towerbody by a gastight weld.

2. An axial flow reaction tower as claiMed in claim 1, characterized inthat said expansion part consists of a plate attached to saidgas-conducting pipe by means of a gastight weld, said plate terminatingin a thin flexible part which is attached to the bottom of said towerbody by a gastight weld.